• The Plant Pathology Journal
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• v.23 no.2
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• pp.70-75
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• 2007

We conducted an inoculation test using nine open-pollinated families of pine trees to evaluate their susceptibility and mortality in different densities of pine wood nematode. Three-year-old nine open-pollinated pine families were inoculated with Bursaphelenchus xylophilus at levels of 3,000, 5,000, and 7,000 nematodes/seedling in greenhouse. There were no distinct patterns in latent period among three densities of B. xylophilus in all families. Most families showed the first disease symptoms of needle discoloration within 12-15 days after inoculation. However, open-pollinated progenies of Pinus densiflora showed the longest latent period because none of one-year-old needles were wilted until 14 days after inoculation with 5,000 and 7,000 nematodes. One-year-old needles were wilted earlier than current needles in all tested families with all densities of B. xylophilus. Current needles were not wilted until 14 days after inoculation in all seedlings. The mortality of all seedlings rapidly increased from 35 days to 49 days after inoculation, and all died within 80 days except two seedlings. A 3,000 nematodes/100 ${\mu}L$ with sterilized distilled water are enough to screen 3-year-old pine seedlings for resistance to B. xylophilus.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.374-381
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• 2011

The purpose of this study is to examine the possibility of early detection of Pine Wilt Disease (PWD) using NDVI (Normalized Difference Vegetation Index) from ADC (Agricultural Digital Camera) imageries. The PWD induces the different patterns of reduction of NDVI between healthy trees and infected trees, due to the withered leaves on the infected trees. Based on these phenomena, the DI showing the NDVI variations of trees by time series was employed to detect the infected trees. To find out the differences of DI level between normal and infected trees, DIs of trees from May to August in 2007 were calculated and these were analyzed with GLM (General Linear Models) in SAS 9.2. As a result, the difference of DI between in June and August shows the most significant level (0.0001). The discriminant analysis was performed between normal and infected trees, using the DI of June and August. As the result, hit ratio of trees and the accuracy of grouping with Jack-knife method were shown 71.9% and 73.5%, respectively. These results showed that the DI is effective to detect the trees infected by the PWD and it is useful to prevent the PWD.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.2
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• pp.36-49
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• 2019

The objectives of this study were to extract "Field Survey Based Infection Tree of Pine Wilt Disease(FSB_ITPWD)" and "Object Classification Based Infection Tree of Pine Wilt Disease(OCB_ITPWD)" from the Research Forest at Kangwon National University, and evaluate the spatial distribution characteristics and occurrence intensity of wood infested by pine wood nematode. It was found that the OCB optimum weights (OCB) were 11 for Scale, 0.1 for Shape, 0.9 for Color, 0.9 for Compactness, and 0.1 for Smoothness. The overall classification accuracy was approximately 94%, and the Kappa coefficient was 0.85, which was very high. OCB_ITPWD area is approximately 2.4ha, which is approximately 0.05% of the total area. When the stand structure, distribution characteristics, and topographic and geographic factors of OCB_ITPWD and those of FSB_ITPWD were compared, age class IV was the most abundant age class in FSB_ITPWD (approximately 55%) and OCB_ITPWD (approximately 44%) - the latter was 11% lower than the former. The diameter at breast heigh (DBH at 1.2m from the ground) results showed that (below 14cm) and (below 28cm) DBH trees were the majority (approximately 93%) in OCB_ITPWD, while medium and (more then 30cm) DBH trees were the majority (approximately 87%) in FSB_ITPWD, indicating different DBH distribution. On the other hand, the elevation distribution rate of OCB_ITPWD was mostly between 401 and 500m (approximately 30%), while that of FSB_ITPWD was mostly between 301 and 400m (approximately 45%). Additionally, the accessibility from the forest road was the highest at "100m or less" for both OCB_ITPWD (24%) and FSB_ITPWD (31%), indicating that more trees were infected when a stand was closer to a forest road with higher accessibility. OCB_ITPWD hotspots were 31 and 32 compartments, and it was highly distributed in areas with a higher age class and a higher DBH class.

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.267-274
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• 2009

This study was carried out to select effective preventive pesticides against pine wilt disease caused by pinewood nematode (PWN), Bursaphelenchus xylophilus on trunk injection. 1,000 fold aquatic solution of abamectin 1.8% EC and emamectin benzoate 2.15% EC were lower mortality (7.3% and 8.3% respectively) against PWN on 1 day after treatment. However effects of abamectin 1.8% EC, emamectin benzoate 2.15% EC, fosthiazate 30% SL and fenitrothion 30% SL were inhibited the reproduction of PWN over 99.6% in Botrytis cineria media. Effect of trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC at the rate of $10\;m{\ell}$ per 10 cm in diameter of breast height (DBH) on mortality of Japanese black pine, Pinus thungergii by inoculated PWN was 0% and 3.3%, respectively at the applied year however when injection of fosthiazate 30% SL were treated with the rate of $5\;m{\ell}$ per 10 cm tree DBH, mortality of tree was 63.3%. Abamectin 1.8% EC and emamectin benzoate 2.15% EC was showed high preventive efficacy representing >90% against PWN at the following year. PWN preventing efficacy of trunk injection was lower in naturally occurred area (mortality of pine tree in control was 11.7% at the first year) of PWN than artificially infected site (mortality of pine tree in control was >76.7% at the first year), PWN preventing efficacy of trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC at the rate of $10\;m{\ell}$ per 10 cm in DBH was 91.5% and 82.9%, respectively, at the applied year and 89.5% and 82.6% respectively at the following year in PWN naturally occurred site. Control efficacy by trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC was more higher in 10 fold dilution with 10 fold high amount of aquatic solution than no dilution with 10 fold less amount of aquatic solution. The preventive effect of trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC at the rate of $5\;m{\ell}$ per 10 cm in DBH was showed 100% at the applied year in PWN inoculated tree.

• The Korean Journal of Mycology
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• v.24 no.2 s.77
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• pp.93-103
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• 1996

In order to find out effect on the inorganic and organic compounds as a soil amendment to control Fusarium wilt of cucumber caused by Fusarium oxysporum f. sp. cucumerinum, this study was conducted during the last two years from 1993 to 1995. According to add 14 inorganic chemicals (1%, w/v) including $Al_2(SO_4)_3$ individually in vitro, these chemicals were confirmed their suppression, and especially Alum, CaO and $Al_2(SO_4)_3$ suppressed not only $20.9{\sim}25.0$ percent on mycelial growth of the fungus, but also inhibited $72.8{\sim}97%$ on conidial germination. $Ca(NO_3)_2$ suppressed mycelial growth only, while KCl, $K_2SO_4,\;NH_4NO_3$, and Urea suppressed conidial germination. The 7 chemicals were finally seleced. Composted pine bark (CPB) suppressed definely more than 90% on conidial germination in the different extract concentration (2,5 and 10%), although mycelial growth on extract medium of CPB and milled alfalfa leaves (MAL) were not remarkable. The antagonist Trichoderma sp. (Tr-3) mixed with an amended soil (1%, w/w) containing composted pine bark showed a good mycelial growth to compete the causal fungus. And the antagonist Pseudomonas sp. (7-1-3) was also confirmed its antagonistic ability with culture filterate. It is known that a CPB soil amendment mixed with the two antagonists (1%, w/w) controlled almost completely Fusarium wilt of cucumber in greenhouse pots and a field experiment. It is therefore expected that biocontrol on Fusarium wilt of cucumber by a soil amendment can be applied to farmmer's fields.

• Korean journal of applied entomology
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• v.57 no.1
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• pp.7-13
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• 2018

Currently, there is no available tool that rapidly diagnoses pine wood nematode (PWN)-infected pine trees in the field. In this study, we synthesized and purified PWN Galectin, which might be an antigen specific to PWN, using the Baculovirus expression system. We used PWN Galectin as an antigen for generating 1,464 fusion hybridoma cell lines secreting monoclonal antibodies (Mabs). Among them, we selected 62 fusion hybridoma cell lines showing high reactivity to PWN Galectin. We further selected 12 fusion hybridoma cell lines showing high reactivity to the standard PWN-infected pine tree phosphate buffered saline (PBS) extract. Additionally, two fusion hybridoma cell lines showing no or extremely low reactivity were used as controls. The selected fusion hybridoma cell lines were subjected to limiting dilutions for selecting and establishing Mab-secreting cell lines showing higher reactivity to the standard PWN-infected pine tree extract than to the standard normal pine tree PBS extract. Moreover, the selected fusion hybridoma cell lines were further selected based on their higher reactivity to PWN protein extracts than to three non-pathogenic nematode protein extracts. The Mab-secreting cell lines established in this study could be used to develop rapid diagnostic tools that can be used in the field or in laboratories for detecting PWN-infected pine trees or PWN.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.159-163
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• 2008

Accurate identification of pine wood nematode, Bursaphelenchus xylophilus is a prerequisite to diagnose the pine wilt disease. However, a fungivorous nematode, B. mucronatus is highly similar to B. xylophilus and it is difficult to differentiate these two species by morphological features. A molecular diagnosis method, ITSRFLP was applied for the identification of B. xylophilus and B. mucronatus from Korea. Genomic DNA was extracted from a single individual nematode and ITS DNA was amplified by PCR. The size of PCR product was approximately 900bp and the sequence data were obtained after cloning. Amplified ITS was digested by 5 different restriction enzymes (Rsa I, Hae III, Msp I, Hinf I, and Alu I) and provided a discriminatory profile for B. xylophilus and B. mucronatus. Besides, B. mucro- natus was determined to have 2 different genotypes, East Asian type and European type also clearly separated by Rsa I and Hae III digestion. European type of B. mucronatus is recently collected from Pinus koraiensis and has not been reported before. ITS sequnce data were analyzed by Restriction Mapper program and the result supported ITS-RFLP pattern. These data indicated that PCRRFLP method is an accurate and simple way for identification of Bursaphelenchus species.

• The Plant Pathology Journal
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• v.29 no.3
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• pp.344-349
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• 2013

Intraspecific variation in morphometry of pine wood nematodes Bursaphelenchus xylophilus and B. mucronatus in relation to geographical locations in South Korea was investigated using morphometric characters (body length, a, b and c ratio, stylet length, and spicule length for a male nematode and V (%) value for a female nematode). B. xylophilus was isolated from Pinus thunbergii in Jinju (1998), Ulsan (2000), Yangsan (2000), Mokpo (2001) and Jeju (2004), and from P. densiflora in Gumi (2001). B. mucronatus was isolated from P. thunbergii in Jinju (1991) and from P. densiflora in Milyang (2001). The body length of male and female B. xylophilus had the highest coefficient of variability and showed significant differences among geographical locations. The V (%) value for female B. xylophilus showed the lowest coefficient of variability, changing little with geographical area and host plant. All morphometric characters in B. mucronatus except for stylet length and female body length showed no significant differences between locations or hosts, suggesting they may not be affected by geographical area or host plant.

• Entomological Research
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• v.48 no.5
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• pp.448-452
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• 2018

The aggregation pheromone of Monochamus (Coleoptera: Cerambycidae) beetles, 2-(undecyloxy) ethanol (hereafter referred to as monochamol), has gained considerable attention because of its usefulness in monitoring and population control of pine sawyer beetles. The hydroxyether structural motif is conserved in pheromones of the subfamily Lamiinae of the Cerambycidae. In this study, we investigated the effects of C10- and C12-chain length alkyl analogs of monochamol, 2-(decyloxy) ethanol and 2-(dodecyloxy) ethanol, on attracting M. saltuairus in Andong, Gyeongsangbuk-do, Korea. The C10 and C12 analogs attracted M. saltuarius when used in combination with ${\alpha}$-pinene and ethanol, but the responses of these alkyl chain analogs were lower than those of monochamol. Furthermore, the addition of either C10 or C12 analog to the use of monochamol with ${\alpha}$-pinene and ethanol had no effect on attraction of M. saltuarius, indicating high sensitivity of M. saltuarius to monochanol. Taken together, the results of this study suggest that chemical communication within a Monochamus species depends not only on monochamol, but also on other semiochemicals.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.12-18
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• 2016

This study was carried out to investigate the change on soil $CO_2$ efflux rates, soil temperature, soil water content and soil pH by thinning intensity treatments (heavy thinning, light thinning, control) of a black pine (Pinus thunbergii Parl.) stand disturbed by pine wilt disease in Wola National Experimental Forests in Jinju, Gyeongnam province. Monthly variations of soil $CO_2$ efflux rates were not significantly different between the thinning and the control treatments (P>0.05). The annual mean soil $CO_2$ efflux rates were $0.58g\;CO_2m^{-2}h^{-1}$ for the light thinning, $0.49g\;CO_2m^{-2}h^{-1}$ for the heavy thinning and $0.45g\;CO_2m^{-2}h^{-1}$ for the control treatments, respectively. There was a significant exponential relation between soil $CO_2$ efflux rates and soil temperature, but no correlation between soil water content or soil pH and soil $CO_2$ efflux rates. The values of $Q_{10}$ were 3.40 for the light thinning, 3.20 for the heavy thinning and 3.06 for the control treatments, respectively. The results indicate that soil $CO_2$ efflux rates in a black pine stand disturbed by pine wilt disease could be affected by thinning treatments.